Apparatus for flame hardening



Sept. 2, 1941. Q MQTT ETAL 2,254,306

v APPARATUS FOR FLAME HARDENING Filed March 18, 1939 INVENTORS I Chester M022 ATTORNEYS Patented Sept. 2, 194i APPARATUS FOR FLAME HARDENING Chester Mott, Evanston, and Malcolm L. Whaley, Chicago, 111., assignors to National Cylinder Gas Company, Chicago, Ill., a corporation of Delaware Application March 18, 1939, Serial No. 262,640

4 Claims.

This invention involves an improved apparatus for flame hardening elongated bodies, such as rods, bars, shafts and the like, and particularly those which are circular in cross-section, and this application is a continuation in part of our coepending application Serial-No. 200,646, filed April "I, 1938.

One object of the present invention is to provide a flame treating apparatus for obtaining uniform surface hardening of a cylindrical body, and efficient cooling thereof.

The invention relates particularly to that type of apparatus in which the cylindrical body, hereinafter referred to as a shaft, is supported in a substantially vertical position and the heating is effected by an annular burner encircling the shaft and relatively movable along the shaft in an upward direction. Directly beneath the annular burner is an annular quenching device for delivering liquid against the hot surface below the burner so that the liquid flows downwardly along the surface of the shaft. Theshaft is preferably rotated so that during the endwise movement of the burner and quenching device, the flame jets and quenching jets travel along a helical path on the surface of the shaft.

As one important feature of the invention and in order to obtain uniform surface hardening, the peripheral velocity of the shaft is relatively high in respect to the velocity of endwise travel of the burner so that the component of the two movements will make a very small angle with the plane of the flame and the plane of the quenching jets.

As a further important feature, the flame jets are very close together so that they merge into a substantially continuous. sheet so that during the endwise movement of the burner and the rotation of the shaft, all portions of the surface around the periphery are equally and uniformly heated. The same arrangement of quenching jets is also employed so that all portions around the periphery of the shaft are equally and uniformly'cooled almost immediately after being heated.

Various other objects, features and advantages of the invention will be apparent from the following particular description, and from an inspection of the accompanying drawing, in which:

Fig. 1 is a somewhat diagrammatic side elevation of an apparatus embodying the present invention, and used for carrying out our improved method,

Fig. 2 is a view similar to a portion of Fig.1,

showing the burner and quenching device on a larger scale,

Fig. 3 is a top plan view of the burner, showing the shaft in cross-section, and

Figs. 4 and 5 are sections taken on lines 4-5 and 5-5 of Fig. 3 respectively.

In the specific form shown, the apparatus for heat treating a. cylindrical body such as a shaft l0, includes a frame structure, which may be in the form of an enclosing casing having a side member H, and upper and lower members i2 and I3. The upper member I2 serves as a support for a suitable chuck or jaw member It for gripping the upper end of the shaft I0, to vertically suspend the latter.

In some cases, it may not be necessary that the shaft Ill be rotated during the 'heat treating.

process, but because of possible variations in spacing between the burner and the surface to be treated, or because of lack of uniformity in the flame around the entire periphery, it is desirable to rotate said shaft to even out the effect of any such variables. To effect such rotation, the chuck l4 may be connected to the lower end of a shaft l5, having a bearing in the upper member i2, and may be driven from any suitable source of power by any suitable means, such for instance as -a belt and pulley i6.

The lower end of the shaft ill may be held against lateral movement in any suitable manner. As shown, there is provided a bracket 68, which may be adjusted vertically in accordance with the length of the shaft to be hardened, and locked in position by any suitable means, as for instance the bolt 9.0. The bracket it carries a centering pin 2 i which may be yieldingly pressed upwardly into a center hole in the lower end of the shaft Id. The spring 22 permits proper engagement of the pin 2! duringlengthening or shortening of the shaft during temperature changes.

The burner 26 shown in Fig. 3 encircles the shaft to be treated, and in the specific form shown, includes a plurality of similar segment torch tips or nozzles 27!, four being shown, each having an inner curved edge 28 extending sub= stantially along an arc of approximately so that the four conjointly form a circular burner encircling and concentric with the shaft iii. The

tips 21 are connected into a burner unit lryv brackets 30, so as to deliver an annular sheet like flame F in a substantially horizontal plane, and directed radially inwardly against the periphery of the shaft to be treated. The separate tips may have separate gas delivery pipes 38, 33,

combustion supporting gases. A single one-piece 5 annular burner might be used..

The individual burner tips 2'! are desirably of the type disclosed and broadly claimed in my co-pending application above referred to, each comprising a pair of interengaging plates 40,

having respectively a series of alternate grooves and ridges, the ridges oi. each plate being disposed in the grooves of the other member, to form the passages 4| through which the flame jets emerge. These passages 4| all communicate with the manifold section 43 of the delivery pipes, and their areas may be varied by proper spacing of the plates or variation in the depth of the grooves. The size of these passages 4| are shown in Figs. 4 and 5 greatly exaggerated for the purpose of clarity, but in actual practice these passages are much smaller, and the number thereof is much greater than that actually shown. For instance, the passages 4| may be as narrow as .025 of an inch or even smaller.

By means of a burner of this type, an even sheet-like curtain of flame is produced, having substantially the same temperature along its length at any given distance from the burner outlets, and the outlets are so positioned, that 3 the separate flame cones produced in front of the several small outlets blend to form a continuous line across the burner outlets and at substantially the maximum temperature.

The burner 26 may be used with any common type of gas mixing device, through which the combustible and combustion supporting gases are delivered. The pipes 45 and 46 may be used to convey the combustible gas such as acetylene,

and the combustion supporting gas such as oxygen, the flow of gas being controlled by suitable valves 47, only one of said valves being shown. From the valves 41 the gases are admitted into a mixing chamber in the handle 35, and then flow to the individual burner tips 21 through the de- 45 livery pipes 3|, 32, 33 and 34.

The quenching device 48 is shown as similar to the burner 26, with its segmental individual nozzle units 49 adjacent corresponding burner tips 21 as shown in Fig. 5, so that said quenching 50 device delivers an annular stream of water W around the heated shaft I, but any suitable annular nozzle may be employed. Water or a suitable quenching agent is conducted to the spray nozzle through the pipe 50, and its flow from a supply pipe 5| is controlled by a valve 52. The burner and nozzle may be clamped together or held in definite spaced relationship in any suitable manner, and if desired, a ballle 49a may be interposed therebetween.

In order to move the burner and quenching device upwardly in unison along the shaft l0, these devices are mounted in spaced relationship on a block 53, which may be moved along the shaft at a uniform rate, and at the desired speed by suitable mechanism. As shown, this block 53 has threaded connection with a vertical screw 54, journaled at opposite-ends, and rotated by any suitable drive means such as the sprocket and chain device 55. As this screw 54 is rotated, the burner and quenching device are moved upwardly from the bottom of the rotating shaft ID, to progressively heat successive portions of the area of the shaft to the critical temperature, and to during desired portion or portions of the path of travel to flame harden only sections of the area if such be required.

By the time the burner reaches the upper end of the shaft, the lower end will have been cooled to a temperature closely approaching that of the water, as all of the water has once flowed down the lower portion, and thusthe shaft may be readily handled at the lower end, and thus easily removed from the apparatus.

The sheet-like flame is in a plane transverse to the axis of the shaft, and the peripheral velocity of the shaft is relatively high in respect to the velocity of endwise travel of the burner, so that the component of the two movements will make a small angle with the planes of the flame and the quenching jets and any non-uniformity of the flame or of the quenching jets in the annular sheets of flame and water, or any lack of perfect concentricity of the shaft and burner will become negligible factors, and uniform hardening 5 is obtained. For instance, a shaft 1.5 in diame- 0 centrifugal force.

The burners 26 may be made in different sizes for use in the hardening of shafts of different diameters. However, it is not necessary to have a different size burner for every different size shaft, since one size burner can efficiently handle shafts of different sizeswithin a certain range.

As many changes can be made in the details of the method and apparatus above described, and many widely different embodiments of this invention can be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

l. A burner comprising a plurality of segmental torch tips, arranged in annular relationship, and having respectively arcuate inner edges conjointly forming a substantially circular contour for concentric encirclement of a cylindrical body to be flame hardened, each tip having parallel closely juxtaposed gas passageways for inward projection of a substantially continuous flame sheet therefrom.

2. A burner comprising four segmental torch tips arranged in annular relationship, and having respectively arcuate inner edges, each extending substantially along an arc of said edges conjointly forming a substantially circular contour for concentric encirclement of a cylindrical body to be flame hardened, each of said tips having a series of parallel gas passageways for inward projection of flame jets therefrom, said passages being so closely spaced as to form asingle continuous flame sheet, the flame sheets from adjacent tips merging together to form a single continuous annular flame sheet.

3. A burner comprising a plurality of segmental torch tips arranged in annular relationship, and having respectively arcuate inner edges conjointly forming a substantially circular contour for conflame hardened, each of said torch tips comprising a pair of plates, each provided with alternate parallel grooves and ridges, the ridges of each plate extending into, but not completely filling the grooves of the other plate, whereby there are formed a row of separate parallel passages for projection of flame jetstherefrom at different angles in respect to the surface forming said contour.

4. A quenching device comprising a plurality 10 of segmental nozzles arranged in annular relationship, and having respectively arcuate inner edges conjointly forming a substantially circular contour, each of said nozzles having parallel passageways with their outlets on their inner ends, said segmental nozzles conjointly operating to project an annular sheet-like curtain of water therefrom. I

) CHESTER. MOTI.

MALCOLM L. 

